1. Field of the Invention
The field of the invention is that of power lasers pumped by coherent optical sources, such as laser diodes.
In the type of structure concerned by the invention, the mode used is a mode a transversal pumping of solid crystals in which rare earth ions are inserted, these ions being the site of the laser effect.
The use of resonant pumping by means of laser diodes has many advantages, among them the obtaining of greater efficiency of conversion of the electrical energy into optical energy and the reduction of the thermal effects at the rod to the minimum. However, the diode lasers used typically have optical/electrical conversion yields that do not exceed 50% in practice. The result thereof is that, in laser rod pumping operations, the unconverted electrical energy, which gets partly converted into heat at the junction of the laser diodes, has to be removed.
2. Description of the Prior Art
One configuration enabling the calories to be removed relies on the use of heat sinks forming the base of the emission strips. The level of energy that has to be removed is high when it is desired to make power lasers pumped with laser diodes. This, therefore, calls for the use of bulky heat sinks which then penalize the designer of the laser head particularly when the entire rod has to be pumped from strips distributed around it.
A known approach to this problem consists in delocalizing the pumping source (consisting for example of laser diodes) and using a multiple-mode optical fiber that conveys the pumping intensity towards the active medium.
However, this approach does not ensure the optimum homogeneity in the illumination of the laser rod, and further implies the use of discrete optical elements that are costly and complicate the mounting operation.
It is an aim of the invention to provide a new structure with delocalized optical pumping sources, overcoming these drawbacks.
More precisely, it is a first aim of the invention to provide a structure of illumination of a laser rod enabling both efficient discharge of the calories released by the coherent optical pumping sources and high homogeneity of the rod pumping operations.
Another aim of the invention is to provide an illumination structure enabling easy coupling, within one and the same assembly, of an oscillator module and an amplifier module.
An additional aim of the invention is to provide a structure that is capable of forming a rigid assembly that can be easily positioned and shifted, notably in the pumping cavity and/or with respect to an axis of amplification when the structure and the rod are used as amplifiers. This goal enables the laser emitter to be easily placed in specific configurations of operation or emission and also provides new functions of homogenization of the illumination of the rod, optimization of the rod in multiple-pass operations or again, for example, cooling of the rod by generation of a hydrodynamic flux.